Electrical contact device for follow-up systems



.. a. w Y 1 2 March 22, T9127. A. P. DAVIS 6 1 835 ELECTRICAL CONTACTDEVICE FOR FOLLOW-UP SYSTEMS Filed Jan. 9, 1925 INVENTOR M ,/4%-MATTORNEY operated fo Patented Mar. 22, 1927.

PATENT OFFICE.

ARTHUR P. DAVIS, 01 BROOKLYN, NEW YORK.

ELECTRICAL CONTACT DEVICE FOR FOLLOW-UP SYSTEMS.

Application filed January 9, 1923. Serial No. 611,680.

This invention relates in general to followup systems and particular yto electrically llow-up systems in which the controlling element is adirection indicator such as a ma netic or gyroscopic compass. TheprincipaIobject of the invention is to provide such an apparatus havinga contact device includin an electrical contact switch or a similarevice actuated by means which will not impart mechanical vibration tothe device.

"Heretofore the follow-up member of a roscopic direction indicatingapparatus as been operated by an electric motor, the apparatus beingarranged so that the controlling member operated the motor switch bymeans of a spring connection. In this system, the spring is mounted onthe gyro frame, and carries a contact point at the free end thereofadapted to engage a contact on the follow-up member. Hence, when thegyro frame rotates with respect to the follow-up member, the motorcircuit is closed by virtue of the spring contact engaging the contacton the follow-up member. The motor then operates until the follow-upmember again assumes its normal position with respect to the gyro frameand the contact switch opens. During the normal use of gyro apparatus,the gyro frame is subjected to severe mechanical vibration due to thehigh speed of rotation of the gyroscope. In a follow-up system, such asthat described in the preceding paragraph, this vibration is transmittedto the contact device on the follow-up member by means of the spring orequivalent connecting member carried by the gyro frame. This makes itnecessary to have high contact pressure between the moving element ofthe switch and the switch contacts, and even with this high pressure itis not possible to secure contact good enou h to insure steady and re-'..able operation 0 the motor; Furthermore, the reaction on the gyroframe, of the moving elements of the switch produces undesirable resultswhich cannot be readily avoided when high contact pressures are usedbetween the actlve surfaces of the contact switch.

In orderto obviate the disadvantages of the contact devices commonlyemployed with follow-up systems, I have devised an improved system ofsuch a character that the mechanical vibration experienced by the switchcontacts carried b the follow-up member. In general, the improved switchmechanism comprises an actuating elementearned by the gyro frame andadapted to operate a switch associated with the followup member. Iprefer to use magnetic means carried by the gyro frame and arranged sothat it may operate the switch supported by the follow-up member. Thismember may carry two contacts and a movable element pivoted betweenthese contacts, the movable element being arranged so that it may beswung to one contact or the other by the magnet1c means associated withthe gyro frame. lVhen the movable element is turned so that it engagesone of the contacts on the follow-up member, the follow-u member rotatesin one direction; and w en the movable member engages the other contact, the follow-up member rotates in the opposite direction. In eithercase, the followup member continues to rotate until it assumes itsnormal position with respect to the gyro frame.

Even though the contact pressure of the improved switch device is veryslight, yet the reaction of this slight pressure may be great enough toproduce a detrimental effect on the operation of the roscope. This smallforce of reaction limits the freedom of movement of the gyro frame andin order to eliminate this imperfection, I have devised a means forneutralizing this force. One means which may be employed for thispurpose consists of one or more electromagnets arranged so that theyexert a force on the magnetic switch-actuatin member carried by the gyroframe, the force being of the proper magnitude and direction toneutralize the force of reaction.

This invention may be best understood by referring to the followingdetailed description which is to be considered in conjunction with theaccompanying drawing. The fi ure of this drawing is a plan view of a folowup system provided with one embodiment of the improved contact device.

The drawing shows a direction findin element comprising a gyroscope 1mounted to rotate on a horizontal shaft 2 supported by the usual frame3. A follow-up member 4 encircles the gyro frame and is adapted to berotated by means of a suitable motor 5. The follow-up member is progyroframe cannot be transmitted to the vided with gearteeth 6 engaged by thepin- 1 ion 7 carried by the shaft of the motor 5. e member 4 issupported by a mercury float bearing indicated at 8.

The follow-up member 4 carries two contacts 9 and 10 rigidly mountedthereon. A movable switch member 11 is pivoted between the contacts 9and 10, the arrangement being such that the movable member may engageeither of the contacts 9 and 10. These contacts are each connected to asource of electrical energy indicated at 12. The movable switch member11 is connected to the motor 5 which, in turn, is connected to thesource of electric energy 12. The gyro frame 3 carries a magnet 13 whichis shown in the form of an ordinary bar magnet, one end of which issupported by the gyro frame, the other end projecting outward into closeproximity to the movable switch member 11 which is attracted by themagnet.

In the neutral or rest portion of the follow-up system, the bar magnet13 and the movable element 11 are in direct alignment' as shown in thedrawing. When relative movement takes place between the gyro frame 3 andthe follow-up member 4, the magnet 13 is displaced with the gyro frame,and causes the movable switch element 11 to rotate in one direction orthe other depending upon the direction of the movement of the gyro framewith respect to the follow-up member If the gyro frame moves withrespect to the follow-up member in the direction indicated by the arrowa, the movable switch element 11 is turned until it engages contact 9.Current then flows in the motor circuit, the circuit being as follows:source of electrical energy 12, movable element 11, contact 9, motor 5,and source of energy 12. The motor 5 then operates to rotate thefollow-up member 4 in the direction of the arrow a until it has reachedits normal rest position with respect to the gyro frame 3, at which timethe switch is opened by magnet 13. If the gyro frame rotates in thedirection indicated by the arrow 6, the motor circuit is closed throughthe contact 10 and the motor operates in the reverse direction to causethe followup member 4 to rotate in the direction of the arrow b untilthe follow-up member again registers properly with gyro frame.

The bar magnet 13 is preferably pivoted on the gyro frame as indicatedat 14. This arangement permits the bar magnet 13 to swing on its pivotto remain in alignment with the movable switch element 11 until thiselement engages one of the segments 9 and 10. WVith this arrangement,the gyro.

frame is not subjected to any sudden force of reaction during theoperation of moving the switch member 11, and flexible action isprovided. After the contact 11 engages contact 9 or contact 10, the barmagnet 13 may be pulled away from the switch element mamas 11 by thecontinued rotation of the gyro frame. This continued movement of the barmagnet 13 introduces a force of reaction tending to retard the movementof the gyro frame. This force need not be great, however, for Ipreferably employ a bar magnet of relatively low strength.

In order to avoid the relatively small force of reaction referred to inthe preceding paragraph, I may employ magnetic means capable ofneutralizing this force of reaction. This magnetic means is arranged insuch a manner that it exerts a force on the bar magnet 13 of such amagnitude and in such a direction that it neutralizes the force ofreaction on the bar magnet 13, this force of reaction being exerted bythe movable switch element 11 on the follow-up member. This magneticmeans may be in the form of one or more electromagnets. Two suchelectromagnets are indicated in the drawing at 16 and 17, theelectromagnet 16 being in circuit with contact 10, and electromagnet 17is in circuit with the contact 9. The electrical circuits are arrangedin such a manner that when the motor circuit is closed through thecontact 9, current flows through the coil of clectromagnet 17 and thiselectromagnet exerts a force on bar magnet 13 in the direction to opposethe force of reaction on this bar magnet. In like manner, electromagnet16 is arranged to exert an opposite force on the bar magnet 13 when themotor circuit is closed through contact 10. The electromagnets 16 and 17are of such a character that the force exerted by them substantiallyneutralizes the force of reaction on the gyro frame and this frame istherefore free to rotate about its vertical axis unrestrained by anyforce transmitted thereto by the switch elements carried by thefollow-up member. In other words, the forcev necessary to operate theswitch member 11 is supplied by the electromagnets 16 and 17 instead ofby the bar magnet 13, this bar magnet serving merely to direct orcontrol the operation of the switch member 11 so as to cause thefollow'up member to rotate in one direction or the other depending uponthe direction of rotation of the gyro frame 3.

From the above description it is apparent that the improved contactdevice comprises means associated with a controlling member foractuating a switch on a controlled member, the arrangement being suchthat the switch is operated positively by the controlling member in sucha manner that mechanical vibrations may not be transmitted from thecontrolling to the controlled member. Furthermore, this inventionprovides means for neutralizing all the undesirable effects now producedon the controlling member of a follow-up system, by the follow-upmemher.

1,ea1,sas

It is tobe understood that the size, pro portion and arrangement of thevarious parts of this invention may be varied with out departing fromthe spirit of the invention which is not confined to the particularembodiments shown and described, but is intended to include suchmodifications thereof as fall within the scope of the appended claims.

I claim:

1. In a system of the type described, the combination of a controllingelement, a con-- trolled element, an electrical contact device carriedby said controlled element, means formoving said controlled element,responsive to the action of said contact device, and ma netic meansassociated with said control ing element for actuating said contactdevice, said means bein incapable of transmitting mechanical vi rationsfrom said controlling element to said contact device.

2. In a system of the type described, the combination of a directionfinding element, a power-driven follow-up element means whereby saiddirection finding element controls said follow element, said means com--prising a reversing contact device supported y said follow-up element,and magnetic means associated with said direction finding element foractuating said contact device, said means being incapable oftransmitting mechanical vibrations to said contact device.

3. In a system of the type described, the combination of a controllingelement, a controlled element, an electrical contact device carried bysaid controlled element, means as sociated with said controlling elementfor exerting a force on said contact device to actuate the same, andmeans for neutralizing the reaction on said controlling element, of saidactuating means.

4. In a system of the type described, the combination of a controllingelement, a controlled element, an electrical contact device associatedwith said controlled element, magnetic means associated with saidcontrolling element for exerting a force on said contact device, saidmeans being incapable of transmitting mechanical vibrations to saidcontact device, and means for neutralizing the reaction on saidcontrolling element, of said force exerting means.

5. In a system of the type described, the combination of a controllingelement, a controlled element, an electrical contact device associatedwith said controlled element, means associated with said controllingelement for exerting a force on said contact device to actuate the same,and magnetic means for neutralizing the reaction on said controllingelement of said force exerting means.

6. The combination of a direction finding element, a power driven followup element associated with said direction finding element, a reversingcontact device supported by said follow up element, magnetic meansassociated with said direction finding element for exerting a force onsaid contact device to actuate the same, and magnetic means controlledby said contact device, adapted to neutralize the reaction on saiddirection finding element, of said force exerting means.

7. In a system of the type described, the combination of a directionfinding element, a follow-up element associated with said directionfinding element, electrically controlled driving means for saidfollow-up element, an electrical contact and a movable switch elementcarried by said'follow-up ele ment and connected to said driving means,and magnetic meansassociated with said direction finding element andadapted to aciu ate said movable switch element. whereby the follow-upelement is caused to follow the movements of the direction findingelement.

In testimony whereof I affix my signature.

ARTHUR P. DAVIS.

CERTIFICATE OF CORRECTION.

Patent No. l, 621,

above numbered patent requiring corre 'word "portion" read "position";trolled by" read "first mentioned magnetic" these corrections thereinthat the same ma Granted March 22, 1927, to

ARTHUR P. DAVIS.

It is hereby certified that error appears in the printed specificationof the P "in circuit with" the Patent Office.

Signed and sealed this 5th day of April.

ction as follows: Page 3, line 71, claim 6, for the words "consnd lines73 and 74, for "force exerting" read and that the said Letters y conformto the record of the case in 2, line 21, for the Patent should be readwith M. J. Moore,

Actfne Commissioner of Patents.

